In the related art, for example, as described in PTLs 1 and 2, a rotating tool such as an indexable end mill is known.
The indexable end mill includes a tool body which is formed in a columnar shape and rotates around an axial line and a cutting insert which is detachably mounted on a plurality of insert attachment seats formed on an outer periphery of the tool body and has a cutting edge protruding from the outer periphery of the tool body toward the outside in the radial direction.
A plurality of chip discharge grooves are formed on the outer periphery of the tool body with gaps therebetween in a circumferential direction, and the plurality of chip discharge grooves gradually extend toward a side opposite to a tool rotation direction around the axial line from a distal end toward a posterior end side in the direction of the axial line.
The plurality of insert attachment seats are arranged on wall surfaces of the chip discharge grooves facing the tool rotation direction with along the chip discharge grooves. The cutting insert is mounted on each of the insert attachment seats.
In this type of rotating tool, it is a common problem to prevent chattering vibrations caused by self-excited vibrations (resonance) during cutting.
In PTL 1, layout lines (that is, imaginary lines connecting predetermined points of cutting edges of respective cutting inserts forming rows along chip discharge grooves) of the cutting edges of the plurality of cutting inserts arranged in the chip discharge grooves are not constantly inclined but are nonuniformly inclined.
In PTL 2, as inclination patterns of layout lines of respective chip discharge grooves, two kinds of inclination patterns such as blade patterns A and B are provided.
In the rotating tool of the related art, self-excited vibrations generated during cutting are decreased and chattering vibrations are decreased by the above-described configurations.